Tenma ST-8920 User Manual

TM

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Pressure & Flow Meter

User Manual

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Part Number: ST-8920

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Table of Contents

1. Features .................................................................................................................... 3

2. Specications .......................................................................................................... 3

3. Button ....................................................................................................................... 4

4. Display Elements ..................................................................................................... 5

5. Changing Setup Options ......................................................................................... 6

5-1. Setup Options ...........................................................................................................................................6

5-2. Entering or Exiting Setup ........................................................................................................................6

5-3. Changing a Setup Option ........................................................................................................................6

5-4. Duct dimension units Setting .................................................................................................................6

5-5. Duct Shape and Parameters Setting ......................................................................................................7

5-6. Choose Duct Shape .................................................................................................................................7

5-7. Parameters Setting ..................................................................................................................................7

5-8. Auto Power Off Mode ...............................................................................................................................8

5-9. Menu Setting .............................................................................................................................................8

5-10. Ciear Memory Setting ............................................................................................................................9

5-11. Measuring Pressure ...............................................................................................................................9

5-12. Measuring Velocity ...............................................................................................................................10

5-13. Measuring Flow ....................................................................................................................................10

5-14. Displaying Temperature ......................................................................................................................11

5-15. Holding the Displayed Readings ........................................................................................................11

5-16. Viewing the MIN, MAX, and AVG Readings ........................................................................................11

5-17. Saving Samples .................................................................................................................................... 11

5-18. Recall and Clearing Sample Data .......................................................................................................11

5-19. Error Codes ..........................................................................................................................................12

5-20. Replacing the Batteries .......................................................................................................................12

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1. Features

• Larger LCD display with backlight.

• Relative time clock on MAX, MIN and AVG provides a time reference for measurement.

•  Pressure, velocity or air ow measurement provides Zero Adjust.

•  Display pressure, Air velocity or air ow plus environment Temperature simultaneously.

• Easy to calculate the area of a rectangular or circular duct.

•  USB interface, USB to UART Bridge Controller.

• Low battery indication, and Auto Power Off mode (Sleep mode) increases.

2. Specications

2-1. General Specications

Operating Conditions 0°C to 50°C

Storage Conditions -10°C to 60°C

Power Supply 1×9V Battery

Low Battery Indicator Yes

Dimensions 203mm×75mm×50mm

Relative Humidity Non condensing (<10°C) 90% RH

(10°C to 30°C)75% RH (30°C to 40°C) 45% RH

(40°C to 50°C)(Without Condensation)

2-2. Manometer specication

Accuracy ±0.3% FSO(25°C)

Repeatability ±0.2% (Max.±0.5% FSO)

Linearity/Hysteresis ±0.29% FSO

Pressure Range 5000 Pa

Maximum Pressure 10psi

Response Time  0.5 Seconds typical

Over range Indicator Err.1

Under range Indicator Err.2

Units Range Resolution

PSI 0.7252 0.0001

mbar 50 0.01

inH20 20.07 0.01

mmH20 509.8 0.1

Pa 5000 1

1 psi*27.68=inH20
1 psi*68.947=mbar
1 psi*703.072= 1*mmH20
1 psi*6894.6=Pa
FSO: Full Scale Output

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2-3. Range of Air Velocity

Air Velocity Range Resolution Accuracy

m/s(meter per second) 1-80 0.01

ft/min(feet per minute) 200-15733 1

km/h(kilometers per hour) 3.6-288 0.1

MPH(miles per hour) 2.24-178.66 0.01

Knots(nautical miles per hour) 2-154.6 0.1

2-4. Rang of Air Flow

Air Flow Range Resolution

CFM 0-99.999ft3/min 0.0001 to 100

CMM 0-99.999m3/min 0.001 to 100

CFM(ft3/min) =Air Velocity(ft/min)×Area(ft2)
CMM(m3/min)=Air Velocity(m/s)×Area(m2)×60
CFM: cubic feet per minute
CMM: cubic meters per minute

2-5. Range of Temperature

Range Resolution Accuracy

°C 0°C to 50°C 0.1 ±1°C

°F 32°F to 122°F 0.1 ±2°F

±2.5% of reading

at 10 m/s

Accuracy is function

0.1 of velocity and
duct 0.01 size

3. Button

1. Press to turn the thermometer on or off.

2. Press “MAN/MIX” to step through the maximum, minimum, and average readings. To exit the MAN/MIX/AVG mode, 
press the “MAN/MIX” button for 2 seconds to return to normal operation.

3. Press “P/V/F” to show the air velocity, press “P/V/F” secondly to show the high and length of a rectangular or the
diameter circular duct, press “P/V/F” thirdly to show the air ow, press “P/V/F” to show differential pressure again.

4. Press “Hold/Zero” to freeze or unfreeze the displayed readings. Press “Hold/Zero” button and hold 2 seconds to
zero out the display.

5. Press “Save/Clear” button to store sample data. Or press “Save/Clear” button to clear sample data in Recall mode.

6. Press “Setup ” button to turn on the backlight. Press it again to turn off the backlight. Press “Setup ” button for
3 seconds to start or exit Setup. (See “Changing Setup Options.”)

7. Press “Unit ” to changes the temperature units. In Setup mode, press “Unit ” to scroll to the Setup option you want
to change or press “Unit ” to increase the displayed setting. In Recall mode, press “Unit ” to select the desired
sample number.

8. Press “Unit ” to Changes secondly showing number units. In Setup mode, press “Unit ” to scroll to the Setup
option you want to change or press “Unit ” to increase the displayed setting. In Recall mode, press “Unit ” to select
the desired sample number.

9. Press “Avg/Rec” button and hold 2 seconds to enter Recall mode. In Recall mode, press “Avg/Rec” to calculate the
sample data. In Setup mode, press “Avg/Rec” button to enter a Setup option. Press “Avg/Rec” again to store the
displayed setting in memory.

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